The problem is that most Mac tools rely on the OSX PDF engine which is known to do what it pleases
(e.g. expand the size)... I can recommend PDF Scanner (
https://itunes.apple.com/de/app/pdfs...10968114?mt=12). It lets you OCR the files and the adjust size for compression. Sometimes gives great results.
Another, although more expensive option, is of course Acrobat Pro. Their ClearScan technology usually produces much smaller files especially for longer documents because it synthesizes fonts from the original documents for OCR, thereby drastically reducing the file size. Just be aware to never save the docs with anything OSX PDF Kit because that will irreversibly ruin the OCR layer. Works best in combination with the monochrome PDFs that you are producing in Preview, or other monochrome PDFs that you could produce in Acrobat.
My usual workflow for Internet Archive PDFs:
- remove unnecessary front and back cover pages
- Crop document in Briss
- Convert to Tiffs with Acrobat
- Reassemble PDF in Acrobat
- Treat with ClearScan
-> small fast PDFs on any reading application including Kindle and Koreader